With the advent of call-handling telephone systems, telephone-based customer service has become pervasive in modern society, especially in business concerns that require direct communication with customers. Many call-handing telephone systems include a call center that has an interactive voice response unit (IVRU), an automatic call distributor (ACD), and a number of live attendants.
Once the IVRU has determined the nature of a call, the ACD automatically identifies and distributes the call to an available attendant, or, when no customer service attendant is available, the ACD places the call in a holding queue (i.e., places the call or caller on-hold). Traditionally, when a call is placed on-hold, the call center may attempt to keep the caller's interest by delivering pre-recorded music and/or greeting messages that identify the next available attendant.